ANALYTICAL IMPROVEMENT OF PNEUMATIC NEBULIZATION IN ICP-MS BY DESOLVATION

We have studied the influences that may be exerted by a desolvation system on a pneumatically generated aerosol, An amount of 80% of the solvent could be extracted from the drain of the desolvation system. The influence of bias potential and sampling depth was studied in order to obtain maximum ion intensity with desolvation. An intensity gain by a factor of 2-5 was realized for a majority of elements in a standard solution. Without desolvation, the sample uptake rate was limited to a value of 1.2 ml/min owing to the appearance of a signal depression; with desolvation, the sample uptake rate could be increased up to 2.5 ml/min without signal depression effects. Exploiting this higher uptake rate, an over-all intensity gain of nearly an order of magnitude in comparison to a conventionally operated pneumatic nebulizer could be achieved for a majority of the elements under investigation. Simultaneously, an improvement in the signal stability was observed, and in particular, interferences by oxides were drastically reduced.